int-bitmask v0.3.0

int-bitmask

Manipulate JavaScript numbers like a bitmask.

Functions

checkBit()

Returns true, false or null depending on checked bit in a given number.

First arg: number. Second arg: bit index.

Sample usage:

checkBit(65, 0); // returns true, as the first bit (index 0) counting from the right is on.
checkBit(65, 1); // returns false, as the second bit (index 1) counting from the right is off.
[...]
checkBit(65, 5); // returns false, as the sixth bit (index 5) counting from the right is off.
checkBit(65, 6); // returns true, as the seventh bit (index 6) counting from the right is on.
checkBit(65, 7); // returns null, which is falsy, as the eighth bit (index 7) is not part of the number.
---
checkBit(-1, 0) // throws Error: Inputs cannot be negative.
checkBit(2.5, 0.5) // throws Error: Inputs must be integers.

setBit()

Takes a number, changes the given bit and returns the new number.

First arg: number. Second arg: bit index. Third arg: new bit state (0 | 1).

Sample usage:

setBit(64, 0, 1); // returns 65
setBit(128, 0, 1); // returns 129
setBit(64, 6, 0); // returns 0
---
setBit(-1, 0, 1) // throws Error: Inputs cannot be negative.
setBit(2.5, 0.5, 0) // throws Error: Inputs must be integers.

toggleBit()

Takes a number, toggles the given bit and returns the new number.

First arg: number. Second arg: bit index.

Sample usage:

toggleBit(0, 6) // returns 64
toggleBit(64, 6) // returns 0
---
toggleBit(-1, 0) // throws Error: Inputs cannot be negative.
toggleBit(2.5, 0.5) // throws Error: Inputs must be integers.